Mortar sight bracket and sight



CCL 30, 1951 E. c. ROBERTS ET AL 2,572,882

MORTAR SIGHT BRACKET AND SIGHT Filed July 2, 1947 3 Sheets-Sheet 1 Zjwvc/nQ/LS) E- E Rmher e@ @aufge E Davisln Oct- 30, 195l E c. ROBERTS ETAL 2,572,882

0 l MORTAR SIGHT BRACKET AND SIGHT Filed July 2, 1947 3 Sheets-Sheet 2 /0 VIE 49 (Q Em A iilllllllllllllllllll E E Ruher5 y Eeurqe E 'Dav JI;

Oct. 30, 1951 I E. c. ROBERTS ET AL MORTAR SIGHT BRACKET AND SIGHTy 3 sheets-sheet s Filed July 2, 1947 UNITED vSTATES PATENT OFFICE Y 2,572,882 MRTR SIGHT BRACKET AND SIGHT Edgar C. Roberts, Arlington, Va., and George B.

Davis, Jr., "Washington, D. C., assignors to the United States of America as .represented by the 'Secretary of `War Application July2, 1947, Serial No. 758,699

IGranted lunder the act of March 3, 1'883, as amended April 1130, 1928; 370 0. G. 757) 2 Claims.

The invention described herein maybe `manufactured and used by or for rthe Governmentfor governmental purposes without the payment 'to us of any royalty thereon.

This invention relates 'to improvements in mortar sights and sighting.

An .object of "the invention "is `'to provide an adjustable 'sight bracket -which will permit easy Cross-'leveling 'of the sight, independently Aof the cross-leveling means for the mortar mount.

Another `object of the invention is to provide a structure 'which will enable a gunner -to return the bore 'axis of a mortar to its originally 'set angular'position, with respect to the earth, lwithout removing cant of l,gun mount caused by unequal subsidence, after ring.

Another 'obj-ect 'of ithe invention fis to enable -a single operator to correct for unequal subsidence of the mortar mount without Aleavin-g Y'his '-station;

Other objects and advantages of the invent-ion will be apparent during the course of the following description. In the accompanying drawings formi-ng apa-rt of this specica-tion, and -inwhich like numerals are `employed. to'designate vlike parts throughout the same:

Figure 1 is a perspective view of a mortar with the invention applied thereto;

-Figure 2 is -an enlarged perspective viewof the sight bracket and parts of the mortar;

Figure 3 'isa perspective of the main body portion of the bracket;

`=Fig-ure=41is aperspective viewof the pivoted hub portion of the bracket;

Figure 5 is -a bottom view l-of the assembled bracket;

.Figure Y6 is a top view of the assembledbracket;

Figure '-7 :is a;seetional view on `the line '.'l-- :of Figure 6; and

Figure 81's 'a sectional rView on the line 8-8 of Figure f6.

In the past it has been the practice to attach sights to mortars V`with certain .fixed relationships which necessitated cross-leveling the gun witheach `subsidence of Ianypart of themountin order to cross-level the sight and bring it back on the target. The present invention aims to simplify the operation of heavy mortars such as the one illustrated in the drawings, whereinlthe usual cross-leveling crank is `dii'cult vto Alreach while observing the cross-leveling -bubble Von 'the sight. v

Referring now to the drawings, wherein Tor the purpose of il1ustration,is shown a preferred embodiment of my invention,..the numeral I0 designates a mortar barrel.

A base plate supports the base of the barrel for movement in azimuth :and elevation.

The outer end of the dbarrel issupported by a bipod i2 which comprises Mlegs 13, an elevating mechanism I4 having a hand wheel i5, a crossleveling mechanism I6 having an operating crank |1., and a traversing mechanism I3 having a hand Wheel |.9. `A saddle -20 is secured tothe barrel l0 and is .formed with an enlargement -2.| for mounting shock absorbers (not shown) housed within tubes 22. Theenlargemen-t 2| carries a tubular member 23 pivotallyengaged with the traversing mechanism I8. A yoke 24 secured to the elevating mechanism 4 and .pivotally connected to the traversing mechanism completes the pivotal iconnec'tion between .the barrel I0 and the bipod I2. The .above description applies to Astructures that are 'known and are used only to illustrate one form of Vgun with which -the hereinafter disclosed invention may be used.

Extending outwardly from the enlargement 2| are shockabsorber rods 25 by means of which-an adjustable sight bracket 26 is secured .to .the gun.

The bracket comprises a main ybody .portion 42l having holes 28 `for receiving the shock absorber rods 25. Nuts Y29 screw-threadedon .theends of the shock absorber rods .securely hold the main bodyportion 2l against the enlargement 2| ofthe saddle '21).

One edge .of the body yportion 211 is struck up to form a stiffening rib 3U.

The body portion v2l is formed at its .end 3| with an opening .32 for .receiving one end of a pivot pin 33, Whose axis Y34 is ,parallel Iwith the bore axis 35 of the lbarrel l0. Thepivot pin is secured in position on the end 3| of the body portion by .a nut '3.6.

` A hub 3.1 .is `mounted. on `the pivot kpin33 for pivoted oscillatory movement about .the axis 34 o'f the .said pin.

The body .portion 21 is formed with an offset 38 .extending from .its edge opposite the rib 3l) and carries a housing 39 in which is `a spring pressed plunger V40.

abutment arm.4| extendsirom thehub 3,1 into the path of '.movement of the plunger ,40. The hub '3] Ais v formed with an adjusting arm 42 which screwv threadedly receives an adjusting screw 43 in a similarly threaded hole 44 near its outer end. The adjusting .screw '43 .abuts the offset^38 of the body portion "2i thus providing resistance to the thrust of the spring pressed plunger 4S, thereby holding the hub .3J in Van adjusted position. A'knob 45 on the screw 43 provides easy ladjustment thereof.

"Thehub 3.1 also Ycarries a fixture arm 46 formed with a dove-tailed yslot 4i for receiving a similarly shaped bracket of a sighting device such as a standard U. S. 'M4 sight` 'The collimator sight 'd8 lis equipped with the usual bubble-type cross-level@ and longitudinal or elevation level '50.

'In accordance with conventional practice, the collimatoris mounted in a bracket 'or frame havving a tang received in slot 41. When so posiaxis 52 which is at all times normal to first axis 34. The line of sight is, of course, normal to the aforesaid second axis. This second axis is parallel to the axis of cross-leveling bubble tube 49 so that, when the bubble thereof is centered, the axis 52 is known to be horizontal. The line of sight of the collimator is parallel to the axis of longitudinal bubble tube 50 for zero deflection so that the proper angle of elevation may be introduced by the elevation scale on knob I in conjunction with the aforesaid bubble tube 50.

A bubble-type cross-leveling device 53 is installed on the tubular member 23 whereby the axis of the traversing mechanism I8 may -be placed in a horizontal position.

It is to be understood that the form of our invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of our invention, or the scope of the subjoined claims.

The operation is as follows:

Let it be assumed that the axis of the shaft by which train is eiected, is originally horizontal and that the line of sight is horizontal. This is accomplished by manipulating handle I1 until bubble 53 is centered. Hand wheel I5 is turned to elevate the mortar barrel to its proper angle to correspond with the range or distance of the target from the piece. This range is determined by the setting of collimator sight 48 and the centeringr of the bubble in longitudinal or elevation level 50. Of course, the bubble in cross level 49 is also centered at this time. y

When the mortarpiece is nred settling and subsidence is not usually uniform, the weapon is no longer correctly laid to give the proper range, and cross leveling bubble 53, and sight bubbles 49 and 50 are no longer centered. It is obvious that by manipulating all the controls including crank Il, the gun can be reaimed. However in a large mortar this would require the service of more than one man, because the man at the sight must constantly keep his eye on the eyeA piece of the collimator, requiring a second man to work crank I1. By means of our novel sight bracket only wheels I5 and I9 and screw 45 need be manipulated by a single operation to correct for unequal subsidence. This is accomplished as follows. VFirst knob 45 is turned to recenter bubble 49. This is eiected because the line of sight is rotated about an axis 34 which is parallel to the axis of the barrel. The line of sight is now level and wheel I9 is rotated to bring this line of sight back on the target. Hand wheel I5 is then operated to reset the piece in elevation to its original Iiring angle. This is accomplished by observing that longitudinal bubble 50 is centered within its tube. Centering of bubble 50 may throw off cross level bubble 49 slightly, hence the procedure is repeated until nal adjustment no longer changes the setting of bubble 49. The entire adjustment is quickly accomplished in less time than it takes to describe,

the procedure. It is to be noted, that bubble 53 is only used when initially laying and setting the mortar. For leleveling after firing and subsidence, this bubble is disregarded.

A single operator is thereby enabled to correct for unequal subsidence of the mortar amount, without leaving his station since he can observe the cross-level bubble 49 and make appropriate cross-leveling adjustments at knob 45 without moving his head.

We claim:

1. For use with a gun of the mortar type including means for supporting the barrel of said gun, a bracket secured to said gun supporting means, hub means pivotally mounted on said bracket for oscillatory movement about an axis parallel to the axis of said gun, screw adjusting means secured to said hub for effecting oscillation and adjustment of said hub about its axis, spring biased plunger means for maintaining said hub in fixed oscillated position, a telescopic sight mounted on said hub including a iirst cross level indicator responsive to actuation of said screw adjusting means, a second longitudinal level indicator mounted on said telescopic sight for adjustment about an axis normal to said hub axis, second screw adjusting means for leveling said longitudinal level indicator, where' by actuation of said first screw adjusting means and said second screw adjusting means will return saidtelescopic sight to its original target after subsidence caused by firing.

2. The combination with a mortar and telescopic sight and means for facilitating subsidence correction for said mortar comprising a bipod, a saddle secured to the `upper end of said bipod for supporting the barrel of said mortar, hand wheel means on said bipod for elevating said mortar barrel, second handle means on said 1 bipod for initially cross leveling said telescopic sight, traversing mechanism forming a part of said saddle and secured to said barrel to train said barrel upon a target, a bracket xedly mounted on said saddle having an opening at one end, a pivot pin secured to said bracket and extending into said opening, a hub mounted on said pin for oscillatory movement about an axis parallel to the boreaxis of said mortar, an adjusting arm forming part of and extending from said hub, said arm having an opening for accommodating an adjusting screw, spring biased plunger means for holding said hub in an adjusted position,`means on said hub for mounting said telescopic sight, a rst cross leveling bubble and second longitudinal bubble forming part of said sight, whereby upon subsidence caused byV firing of said mortar, said hand wheel, traversing mechanism and adjusting screw are actuated to reaim said motor upon its original target without the use of said second cross leveling handle means.

EDGAR C. ROBERTS.

GEORGE B. DAVIS, JR.

REFERENCES CITED The following references are of record in the` le of this patent: Y

UNITED STATES PATENTS 

